1. Field of the Invention.
The present invention relates to an underwater acoustic system and more particularly to a reverberation backscatter measurement system.
2. Description of the Prior Art.
There is an increasing need to be able to accurately identify underwater objects by means of sonar systems and a continuing effort exists on the part of many researchers to develop accurate and reliable information from the reflected signals or backscatter of sonar systems. There are many factors and problems which contribute to preventing the accurate identification of an underwater object from its reflected signals. It has been found that such factors as the speed of the sound in the media, the range of the target, the frequency of the transmitted acoustic signal, the pulse width of the transmitted acoustic signal and the transducer characteristics contribute in different ways to making it difficult to determine the meaning of the reflected sonar signals. Various of these factors contribute in different ways to making it difficult to determine actual target strength (TS) which is a measure in decibels of the reflected target signals. Various of these factors also contribute in different ways to making it difficult to determine actual scattering strength (S) which indicates the amount of reflected signal per unit volume as compared to the transmitted signal per unit volume. It has been also found to be quite difficult to effectively process data that has been reflected by underwater targets, especially when it is being received over long periods of time.
The present invention overcomes many of these problems by providing a real-time reverberation backscatter measurement system that compensates for many degradation factors and makes it possible to very accurately identify underwater objects from their reflected signals.